THE WORLD’S NEXT MAJOR RARE EARTH PRODUCER

Sichuan is proud of having a rich and diverse supply of natural resources thanks to its complex geological features and ideal mineralizing conditions. A total of 132 different types of mineral resources, or 70% of the country's total, have been found. 94 types have been confirmed to have sizeable reserves, 32 of which rank among China's top 5 in terms of secured reserves.

The Lushan Project

 

Location: Lushan County, Ya’An Prefecture, Sichuan Province, People’s Republic of China.

The Lushan Rare Earths’ Deposit:

  • Located in Ya'an, Sichuan Province's center;
  • Infrastructure for the mining and production process available locally and regionally;
  • Strong local community support for mine development;
  • Established conditions for the mine development.

 

Geology and Mineralization

The area's basement rocks are Precambrian charnockitic granulites and gneiss. These were invaded by a variety of alkalic intrusions during the Jurassic/Cretaceous period. There are several large alkaline intrusions as well as numerous small plugs and dykes in the Lushan project area. Alkaline syenitic rocks with locally associated carbonatites are the dominant lithologies. The project is envisioned as a solid surface – approximately 1,400 m in diameter – displayed as bedrock.

The carbonatite is better exposed along the north-eastern side and is generally considered to form a ring structure with a minor area along the north-western edge. The vent complex appears to be a multi-phase intrusion characterized by various carbonatites and breccias exhibiting a spectrum of alteration from potassic fenitization to low temperature hydrothermal / carbo-hydrothermal overprinting, according to data from surface mapping and drill core. The vent complex cuts through the massive nepheline syenite intrusion's western end, however, the external contacts on the vent's western and northwestern sides are concealed behind recent surficial eluvial deposits.

Carbonatite, fenite, and breccia are the main lithologies found in the project's vent complex. Although subordinate ferrocarbonatites are known, the carbonatites are mostly grey calcic carbonatites. The fenites appear to form an aureole around the carbonatite and are dominated by K-feldspar rocks. They are thought to have originated as a result of metasomatism caused by carbonatite intrusion.

The breccias range in size from obviously abraded pebble-sized fragments (pebble dykes) to angular blocks with considerable volumes of breccia in which the fragments appear to have moved little or not at all. The breccias are classified into two types: feldspathic-rich breccias and carbonatite-rich breccias, and are considered to be linked to high-level explosive processes during the vent complex's creation.

The main zone of REE mineralization can be found on the area's northwestern side. Carbonatites, fenites, and breccias contain REE mineralization and are exposed intermittently over a surface area of 350 m by 100 m. Beyond the current drilling limitations and below the deepest vertical intersection of about 350 m below the surface, the REE deposit is untested to the northwest and southwest, and there is considerable regional exploration potential in the area and neighboring carbonatites. A carbonatite plug with substantially sub-vertical edges is thought to constitute the mineralized body.

Three geological domains have been identified in the Lushan deposit for the Mineral Resource concept: a carbonatite domain, a fenite domain, and a 'mixed' domain comprised of breccia and/or finely intermixed carbonatite and fenite.

REE mineralization is primarily found in carbonatites, but it can also be found in fenite and mixed domains. Synchysite and apatite are the most common REE-bearing minerals. When compared to apatites found in typical carbonatite deposits, the apatite is abnormally rich in heavy rare earth oxides (HREO). The REE mineralization is strongly connected with strontianite and baryte, and it is thought to have originated after the carbonatite intrusion through sub-solidus hydrothermal alteration.

 

The Lushan Deposit’s Geological Model

  • Well-studied geology and controls on rare earth mineralization.
  • RE-enriched dykes (REDs) infiltrated into a RE-bearing carbonatitic phlogopite breccia phase (CPB). Enriched high-grade REE-bearing horizons from surface to 80-100m depth.

 

Resource Delineation Drilling

  • Extensive drilling completed at Lushan Deposit.
  • 266 holes were drilled for a total of 17,881 meters, with hole spacing from 17-34m.
  • 16,291 meters assayed at 1meter intervals for resource estimation purposes.

 

Weathered CPB Intruded by Highly RE Enriched Dykes

 

CPB-carbonatitic phlogopite breccia

REDs-rare earth enriched dykes

 

The Lushan Resource Modelling

 

RARE EARTH INDUSTRY DELEGATION VISIT TO LUSHAN DEPOSIT

 

RARE EARTH RESERVE BLOCK MODEL

 

THE LUSHAN RARE EARTH RESERVE ESTIMATE

2019 TREO Reserve Estimate

Cut-off Grade (TREO)

Tonnes

 (Millions)

Average Grade (TREO)*

Contained TREO (Tonnes)

Proven TREO Reserves

1%

12.69

1.88

281k

Probable TREO Reserves

1%

22.26

1.49

389k

Total TREO Reserves

1%

34.95

1.64

671k

 

Most rare earth projects follow a three-stage metallurgical process:

  • Beneficiation entails crushing and grinding (comminution) of run-of-mine ore, followed by physical separation and upgrading of rare earth host minerals while rejecting gangue minerals. Gravity separation, magnetic separation, and froth flotation are some of the techniques used.
  • Chemical dissolution of the rare earth host minerals employing acidic or alkaline processing stages, generally at extreme temperatures, is known as hydrometallurgical recovery. Purification measures are then performed to eliminate any undesired elements that dissolved with the rare earths during the dissolution process. The resulting solution can be delivered directly to a separation stage if one is available on site, or it can be precipitated to produce high purity, mixed rare earth chemical concentrate that will be shipped to another separation facility.
  • Separation is the process of isolating individual or groups of rare earths into marketable products based on the needs of the end consumers. Selective oxidation and solvent extraction are common techniques.

Due to the highly varied mineralogy of rare earth resources, the first basic processes tend to vary considerably between projects. To guide the development of the beneficiation and hydrometallurgy phases, it is critical to commit sufficient time and resources to understanding mineralogy.